Crystallization and mechanical properties of carbon nanotube/continuous carbon fiber/metallocene polypropylene composites

Abstract

Abstract In this work, a high fluidity polypropylene prepared with the metallocene catalyst (mPP) was used as matrix, carbon nanotube (CNT) and continuous carbon fiber (CCF) were added to prepare composites, and their mechanical properties, melting and crystallization behavior were investigated. In the mechanical properties, the effects of tension force in the preparation process and compatibilizer maleic anhydride grafted polypropylene (MAPP) on the tensile strength of the composites were researched. The results show that the tensile strength of the composites increases first and then decreases with the increase of tractive force. In addition, the melting and crystallization behaviors and dynamic mechanical behaviors of mPP, CNT/mPP and CNT/CCF/mPP composites were characterized and studied by a differential scanning calorimetry (DSC) and dynamic mechanical analyzer (DMA). The results show that the melting point (T m), crystallization temperature (T c) and storage modulus (E′) of CNT/mPP are all increased by adding 1 wt% CNT, especially the T c is increased by 8.8 °C. It shows that after CNT was added to mPP as inorganic carbon material, it plays a prominent role in heterogeneous nucleation. After CCF was composited with CNT/mPP, the composites with CCF content of 30 and 42 wt% were prepared, and their T m, T c, crystallinity (X c) and E′ were all improved, especially E′ was greatly improved, such as the initial E′ was increased by 5.64 and 11.74 times. Even at the end of the curve, the E′ of the composites with CF is still significantly higher than that of mPP and CNT/mPP. It indicates that adding CCF will greatly improved the deformation resistance and load deformation temperature of mPP.